Means for preventing dead-centering



(No Model.)

R.' WATT. MEANS POR PREVBNTING DEAD GBNTBRING. No. 435,267.- l PatentedAug. 26, 1890.

UNITED f STATES PATENT OFFICE.

ROBERT IVATT, OF BROOKLYN, NEIV YORK.

MEANS FOR PREVENTING DEAD-CENTERING..

SPECIFICATION forming part of Letters Patent No. 435,267, dated August26, 1890.

Y i Application filed March 12, 1890:. Serial No. 343,624. (No model.)

To all whom t may concern:

Be it known that I, ROBERT WATT, a citizen ofthe United States, residingat Brooklyn, in the county of Kings and State of New York,. haveinvented certain new and useful Im' in the claims forming a part of thisspecifisewing-machines and the like.

dent, however, that the invention may be emcation. Y

In the accompanying drawings, illustrative of my invention, Figure 1represents a sectional view of one. embodiment thereof,V taken on apla-ne indicated by the line 1 1 of Fig. 2; and Fig. 2 representsafrontelevation of the same, partly in section.V

Similar numerals of reference indicate simil lar parts in both views.

For purposes of illustration I have shown my invention as applied to afoot-treadle mechanism of a familiar type adapted to be used foroperating light machinery, such as It will be evibodied in power-drivenmachines for heavier work, and Ido not therefore restrict myself t0 itsemployment with the particular motive mechanism shown, which constitutesbut one of its embodiments in practice.

Referring to the drawings, 3 4' indicate the supporting-standards of afoot-treadle mechanism connected at top by the table 5 and strengthenedand braced in the usual manner to form a substantial frame-work ormounting for the operative parts.

Upon the cross-shaft 50 is mounted the oscillatory foot-treadle 6,having a rearward projection 8,`pivotally connected to lthe swingingdriving-rod or pitman 9, eccentrically connected by means of thecrank-pin 10 to the band-wheel 11, mounted upon the standard 4.

The parts described constitute an ordinary type of foot-treadlemechanism. To prevent dead-centering in this and similar mechan isms, Icombine therewith an attachment of my invention whereby latent energy isstored connect to the driving-rod 9 a bar or rod 12, of

springy or resilient material, provided at its free end with afriction-roller 13, as shown. This friction-roller passes within ahollow casting 14, connected by a bolt 15 and nut 16 to the standard 3,and is provided with a circular slot 17 and set-screw 18,wherebyit maybe adjusted and fixed rigidly to the standard. The casting is alsoprovided with a rim or flange 19, serving as a surface of contact forthe friction-roller, as will hereinafter more fully appear.

The operation of my invention will be apparent. Thus during theoscillation of the dri-ving-rod the point of attachment 20 of thespring-bar 12 describes a regular geometric curve whose longer axis isin the line of deadcenter. The outer end of the spring-bar 12 and thefriction-roller 13 would, if unrestrained, describe a like curve. I soarrange the adjustment of the casting, however, that the friction-roller13 will come in contact with a portion of the rim 19 just in front ofthe dead-center line, so that in order to pass the surface of contactthe friction-roller will be deflected out of the regular curve it woulddescribe if unobstructed. This deiiection causes the spring bar or rod12 to bend at its outer end, thereby storing up energy in said bar orrod. The friction-roller passes the surface of contact just before thedead-center line is reached, (on the upward and on the downward strokeof the driving-rod,) and as a consequence its sudden release fromrestraint enables the stored-up energy in the deflected spring bar orrod to come into action. The effect is to throw the driving-rod forwardwith a force dependent upon the amount of such stored energy, therebycarrying it past the dead-center line. It is evident that the amount ofdeflection of the spring bar 0r rod will depend upon the adjustment ofthe casting 13, which can be regulated so as to bring the restrainingguide-surfaces of the rim 19 to IOO a greater or less distance Withinthe path of movement of the friction-roller, according as it is desiredto store `up a greater' or less amount of energy in the spring bar orrod.

For convenience I provide the lcasting with a single continuous rim; butit is not essential so to do, inasmuch as only portions of said rim areactually employed as the restraining guide-surfaces. In someinstances,also, I may dispense with the employment of a friction-roller and permitthe free end of the spring bar or rod to come directly in contact withthe restraining guide-surfaces, al though it will be found preferable toemploy such friction-roller to lessen thework imposed upon the operatorand to insure the greatest regularity of movement.

Having thus described my invention,what l claim isy 1. In a device forovercoming dead-centers, the combination, with the driving-Tod, of aspring bar or rod connected at one end thereto and a restraining-guideWhose acting surfaces are interposed in the path of movement of the freeend of said spring bar or rod and in advance of the dead-center line,substantially as described.

2. In a device forovercoming dead-centers,

`19, substantially as described.

4. In a device for overcoming dead-centers, the combination, with thedriving-rod 9, of a spring bar or rod 12, connected thereto and havingat its free end thn friction-roller 13, and the hollow casting 14,having a guiderim 19, a central pivot for said casting, and I means foradj nsting said casting about said pivot, substantially as described.

In testimony whereof I alix my signature in vpresence of two witnesses.

ROBERT WATT. Witnesses:

JAMES F. MANsIL, EDWARD CHAPPELL.

